Drawing board



May 25,1926. 1586mm H. H. CHRISTIAN, I I

DRAWING BOARD Filed'May 29, 1923 2 Sheets-{Sheet 1 May 25 1926.1,586,061

H. H. CHRISTIIAN DRAWING BOARD Flled May 29. 1920 ;Z9-A3- ,0? a, I Y 7gmwtu Patented May 25 1926 UNITED STATES PATENT OFFICE.

HARRY H. CHRISTIAN, F SEBASTOPOL, CALIFORNIA.

DRAWING BOARD. 4

Application filed May 29, 1923. Serial No. 642,233.

' bined features to take the place of traingles,

protractors, and parallel rulers on a drawing board.

Other objects of the invention will appear upon consideration of thefollowing detailed description and accompanying drawings, wherein:-

Figure 1 is a plan View of the device,

Figure 2 is an edge elevation,

' Figure 3.is a cross section on the line 33 of Figure 1,

Figure 4 is a cross section on the line H of Figure 1,

Figure 5 is a cross section taken on the line 5-5 of Figure 1,

Figure 6 is a cross section on the line 6-6 of Figure 1, and

Figure 7 is a cross section on the line 77 of Figure 6.

Referring to the drawings by numerals, the drawing board 1 is providedat one of its side edges with a transverse groove 2 which extendsentirely across the board and is dovetailed as shown. The T-square 3 isprovided with a head 4 which is fitted in the dovetailed groove 2, andthis head is divided in two sections 5 and 6. Sockets are provided inthe sections 5 and 6 of the head 4 to receive spring element which actsto spread the sections 5 and 6 apart so that they will be firmly held inthe dovetailed groove 2. A thumbscrew 8 passes through the shank 8 ofthe 'T-square and into the head 4 for clamping the T-square to the boardin any desired adjusted position. The edges of the T-square aregraduated and the edge of the groove 2 is also graduated to permit theuser to make any desired adjustment without the use of scales or rulers.

The movable scale 9 is attached to the shank 3 of the T-square and isdisposed at right angles thereto, and is secured in position by athumbscrew 10 which will be screwed downwardly to press against theT-square for holding the scale 9 in anydesired adjusted position. I

Near the opposite end of the scale 9, a protractor 11 is pivotallymounted, and this consists of the semi-circular plate 12 and theprotractor arm 13,which has its edges graduated as shown. Thepivot'member 14 connects the protractor to the scale 9 and a thumbscrew15 is employed to clamp the protractor in any desired adjusted position.The marginal edge of the protractor plate 12 is graduated in the usualmanner and registers with graduations 16 on the end of the. scale 9, sothat the angular position of the arm 11 may be determined by swingingthe protractor on its pivot. Instead of connecting the protractordirectly to the scale 9, a sleeve 17 is provided on the scale which, asshown in cross section in Figure 7, fits over the edges of thescale andis provided with a screw 18 adapted to clamp the sleeve in any desiredadjusted position. The screw 14 is connected to the sleeve as shown inFigure 6 and the thumbnut 15 may be employed to tighten or loosen theprotractor. on the sleeve. The sleeve, of course, may be longitudinallyadjusted on the scale 9 to move the protractor to any desired positionwith re-.

protractor may be fixed at any angle so that the T-square, scale andprotractor may be used without the use of triangles or separateimplements such as are now generally employed.

Minor changes may be made in the details of construction withoutdeparting from the spirit of the invention or the scope of the claimhereunto appended.

What I claim is:

Drawing apparatus comprising a board having a groove, a T shaped squarehaving a head composed of sections which are normally sildable in thegroove, the sections being provided at their inner edges with alignedsockets, coil springs having their end portions housed within thesockets and the said springs having their axes disposed transverselywith relation to the longi- 100' tudinal dimension of the sections, saids rings being under tension and with a tenency to hold the outer edgesof the sections in frictional contact with the sides of the groove, ablade fixed to one of the sections at a point midway between the axes ofthe coil sprin and disposed transversely of both of the sections and ascrew threaded through the blade and having a conical end portionentering between the sections and adapted to spread the sections to fixthe 1" 110 square with relation to the board, the axis of the screwbeing disposed in a plane at an angle to the plane in which the axes ofthe coil springs lie.

In testimony whereof, I have aflixed my 1 signature.

HARRY H. CHRISTIAN.

